#include<stdio.h>

int main (void)
{
	int i;
	int n,flag,denominator;	
	double sum,item;

	
	printf("Enter n:"); 
	scanf("%d",&n);
	
	flag = 1;
	denominator = 1;
	sum = 0;
	for (i=1;i<=n;i++)
	{
		item = flag * 1.0/denominator;
		sum = sum + item;
		denominator = denominator + 2;
	}
	
	
	printf("sum=%.3f",sum);
	


	
	return 0;
}
